Motor fuels



United States Patent Ofi 3,373,005 MOTOR FUELS Edmund L. Niedzielski, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed May 1, 1964, Ser. No. 364,290 12 Claims. (Cl. 44-69) This invention relates to motor fuels which comprise mixtures of hydrocarbons boiling in the gasoline boiling range in which from 15 to about 75 volume percent are aromatic hydrocarbons and which contain tetraalkyl lead antiknock compounds and lead appreciators which are certain polyacylated nitrogen bases.

Recent changes in the design and arrangement of gasoline engines have made possible significant increases in the efficiency of such engines which have been converted bythe designers of motors and trucks into increased power, savings in operating costs, and greater convenience for motor car and truck owners and passengers. These changes in engine design have involved increases in compression ratio along with changes in combustion chamber shape and in the timing of the combustion process which have put increased stress on the motor fuel and its components, with increased tendency for the fuel to knock. Fuels with increased resistance to knock, that is, with higher antiknock quality, are therefore required for satisfactory operation of such engines.

Methods for increasing the antiknock quality of gasolines and their resistance to knock which have been available in the past are becoming inadequate for further increases in antiknock quality at reasonable cost. One common method of increasing motor gasoline octane quality has involved changes in refinery processing methods by which motor fuel components have been made. Such changes in processing methods have included production of olefinic and aromatic components of high antiknock quality boiling in the range suitable for use as motor gasoline components by such processes as hydrogenation, alkylation, polymerization thermal cracking, catalytic cracking, aromatization, thermal reforming, and catalytic reformmg.

Another very common and practical way of increasing the antiknock quality of motor gasolines has been the addition of tetraalkyl lead antiknock compounds. Increasing concentrations of these compounds have been used to provide the high antiknock quality desired. In all gasolines, however, increasing the concentration of such tetraalky-l lead antiknock compounds is less elfective in further raising the antiknock quality of a gasoline which already contains a moderate amount of a tetraalkyl lead antiknock compound. This is especially more true with the highly aromatic gasolines than with the earlier more paraifinic and olefinic gasolines. In the more highly aromatic gasolines, the antiknock effectiveness of tetraalkyl lead antiknock compounds is particularly reduced at higher concentrations of the tetraalkyl lead antiknock compounds, that is, the response of these gasolines to the last incremental amount of the antiknock compound is decreased. Thus, the addition of a third gram of lead as tetraalkyl lead antiknock compound to a typical aromatic premium grade motor gasoline may increase the octane rating of the gasoline by about 1.8 Performance Numbers, but the addition of the fourth gram of lead to the 3,373,005 Patented Mar. 12, 1968 ice same gasoline already containing three grams of lead may only increase the octane rating by another 0.9 Performance Number. Such reduced lead susceptibility at higher lead concentrations frequently makes unattractive and economically impractical the further increase of octane number or antiknock quality by adding ever larger amounts of tetraalkyl lead antiknock compounds to gasolines which are already high in their content thereof and also high in their content of aromatic hydrocarbons, such as are present in reformate stocks.

The freedom of refiners to increase the amounts of tetraalkyl lead antiknock compounds added to motor gasolines has also been limited by the desire to keep lead concentrations as low as practical in order to avoid health hazards possibly involved in the handling of leaded motor gasolines and from atmospheric contamination by exhaust gases containing lead compounds. Because of these desires, the commonly accepted maximum lead concentration of motor gasolines is now 4 grams of lead per gallon. Other reasons for not further increasing the amounts of tetraalkyl lead antiknock compounds used include the possibility of increased engine malfunctions due to spark plug fouling, preignition, and other undesirable results of increased or changed lead residues remaining in engine combustion chambers.

In spite of these desires to keep the amounts of tetraalkyl lead antiknock compounds present in motor gasolines as low as practical, the concentrations used have increased significantly, as the addition of such compounds has been a practical way to increase antiknock quality, and many gasolines containing close to 4 grams of lead per gallon have been produced.

One method which has been proposed for obtaining the higher antiknock quality required by modern gasoline engines is the use of lead appreciators which are used in conjunction with the tetraalkyl lead antiknock compounds in highly aromatic gasolines. A lead appreciator is not itself an antiknock agent but, when it is used in conjunction with a tetraalkyl lead antiknock compound, a higher antiknock quality or octane rating is obtained than with the tetraalkyl lead antiknock compound alone. Among the types of compounds suggested for use as lead appreciators are carboxylic acids like acetic and propionic acids; carboxylic acids containing hydroxy, alkoXy, and keto groups in their structure; carboxylic acid anhydrides; esters of carboxylic acids and alcohols of several types; lactones; aldehydes; ketones and beta-diketones; and compounds of several of these types together with aryl amines.

While the use of such compounds as lead appreciators has been proposed and widely studied, they have actually been used very little. For instance, the antiknock appreciating effect of many carboxylic acids and their esters has been described by W. R. Richardson and coauthors in the Journal of Engineering Data, vol. 6, pages 309 to 312 (1961), and in Canadian Patent 634,894. Shortchain carboxylic acids like acetic acid are effective antiknock appreciators but are unattractive for commercial use because of their easy water extractability. They also react with alkyl lead antiknock compounds to form insoluble alkyl lead salts, and their acidity promotes colorforming reactions of aromatic diamine antioxidants. The use of salts of such carboxylic acids and amines as antiknock appreciators has been described in the above mentioned article by Richardson (ammonium and aniline salts), in U.S. Patent 3,009,792 (N-methyl cyclohexylamine salt), and in Canadian Patent 635,167 (arylamine salts). Such salts in many cases interfere with the separation of water from gasolines and are therefore undesirable gasoline additives. Other nitrogen-containing compounds described as antiknock appreciators include salts of cyanohydrins (US. Patent 3,021,205) and salts of reaction products of aldehydes and hydroxylamine (US. Patent 3,021,204). Such compounds are relatively expensive and tend to be of low solubility.

It is an object of this invention to provide motor fuels which have improved antiknock quality for modern high compression engines. Another object is to provide motor gasolines with higher antiknock ratings than can be obtained economically by changing the composition of the gasolines by increasing the amounts of high-octane components they contain or by increasing the concentrations of tetraalkyl lead antiknock compounds therein. A further object of this invention is to make practical the production of gasolines of higher antiknock quality than has been practical in the past because of the desire to limit the maximum amount of tetraalkyl lead antiknock compounds added to motor gasolines. Other objects are to provide new compositions of matter and to advance th art. Still other objects will become apparent from the discussion below.

The above and other objects can be accomplished in accord with this invention by a motor fuel which consists essentially of (a) A mixture of hydrocarbons boiling in the gasoline boiling range in which from to about 75 volume percent are aromatic hydrocarbons,

(b) An antiknock quantity of at least one tetraalkyl lead antiknock compound,

(c) At least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and

(d) From 1 to about 30 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound,

(c) said lead appreciator consisting of at least one polyacrylated nitrogen base which has the formula wherein R is a hydrocarbon radical of 1-7 carbon atoms devoid of aliphatic unsaturation, R is a member of the group consisting of hydrogen and hydrocarbon radicals of l-7 carbon atoms devoid of aliphatic unsaturation, at least two of the R and R groups are alkyl radicals of 1-7 carbon atoms, n is zero to 1, p is zero to l, and nis 1 when p is 1.

It has been found that the polyacylated nitrogen bases, as above defined, significantly improve the response of such mixtures of hydrocarbons to the antiknock activity of the tetraalkyl lead antiknock compounds, although such polyacylated nitrogen bases exhibit no, or substantially no, antiknock properties in and of themselves, that is, in the absence of a tetraalkyl lead antiknock compound. The improvements in the antiknock performance (i.e. the performance number) of such leaded motor fuels are especially significant in high performance number motor fuels because increases in performance number as are achieved by this invention are otherwise difficult to achieve or can only be achieved at greatly increased cost by the use of additional quantities of tetraalkyl lead antiknock compound or by more extensive refining and blending techniques.

The polyacyl derivatives of nitrogen bases, contemplated for use in the motor fuels of this invention, are effective lead appreciators of a new Class which are essentially free of the disadvantages of the lead appreciators of the prior art. They are chemically neutral compounds and therefore do not react with tetraalkyl lead antiknock compounds or promote colorforming oxidation of arcmatic diamine gasoline additives, They are essentially non-polar and therefore are adequately soluble in gasolines and do not interfere with the separation of water. They can be made from readily available intermediates by simple processes and are therefore relatively inexpensive. They are either low melting solids or liquids at ordinary temperatures which are adequately soluble in gasoline-type hydrocarbons for use at the concentrations recommended. They are relatively stable organic compounds and unreactive with the additives normally present in motor gasolines at their usual concentrations. Thus, they are particularly suitable for use as gasoline additives.

It has been found that only the defined class of polyacylated nitrogen bases are lead appreciators, other acylated nitrogen bases being ineffective for such purposes. Thus, the monoacyl derivatives of ammonia (like acetamide and benzamide) are not lead appreciators as they might have been expected to be from their close chemical similarly to many other derivatives of carboxylic acids which have been found to be lead appreciators. Also, the diamides in which one acyl group contains an aryl radical and the other acyl group contains an alkyl radical (like acetylbenzamide) are not lead appreciators while polyacylamides containing two alkylacyl groups (like triacetamide and diacetylbenzamide) are lead appreciators. Further evidence of the difference between the polyacylated nitrogen bases of this invention and other similar compounds will be apparent from the further description presented hereinafter.

The motor fuels, used in practicing this invention, are composed of a mixture of hydrocarbons boiling in the gasoline boiling range, from 15 to about volume percent of said hydrocarbons being aromatic hydrocarbons. They may be commercial gasolines, such as those described by ASTM Method D 439 and Military Specification MlLG-3056, or a blend of non-aromatic and aromatic hydrocarbons of the types normally present in such gasolines. For example, the motor fuel may be a blend of any of the types of refined hydrocarbon streams normally produced in oil refineries, such as catalytic cracked stocks, catalytic reformed stocks, thermally cracked stocks, thermally reformed stocks, polymerization products, and alkylation products, including synthetic hydrocarbons not normally present in crude oil as well as hydrocarbons which are normally present in crude oils such as are in what are commonly called straight run and casinghead stocks.

Typical aromatic hydrocarbons which are essential components of the gasoline compositions of this invention and which are of the character of those aromatic hydrocarbons produced by catalytic and thermal reforming of refinery streams are the monoalkyl and polyalkyl benzenes such as toluene, ethylbenzene, the xylenes and the trimethylbenzenes, diisopropylbenzene, cumene, and the like which can be present in normal refinery streams boiling in the boiling range of typical motor gasolines. These hydrocarbons can be obtained directly from petroleum as in refining certain more aromatic crude oils, by reforming non-aromatic refinery streams as described above, from coal tar aromatic fractions obtained by destructive distillation of coals and other carbonaceous fuels, or from any other source of such hydrocarbons.

Typical catalytic cracked refinery stocks which may be utilized contain from about 6 to 25 volume percent aromatics and about 29 and 44 volume percent olefinics, the rest being saturated hydrocarbons. Catalytic reformed stocks run higher in aromatics, usually 40 to 70 volume percent, and are lower in olefins. Synthetic alkylates are essentially saturated hydrocarbons, high in isoparaffins. Refinery stocks such as these are blended in various proportions for the production of commercial fuels for spark ignition internal combustion engines. These fuels norm-ally boil within the range of about 80 F. to 440 F. Blended fuels for commercial use, such as those for automotive use, contain on the average from about 10 to about 55 volume percent aromatic, up to about 30% olefinic, with the rest saturated hydrocarbons.

The motor fuels utilized in the practice of this invention contain at least 15 volume percent and normally not more than about 75 volume percent aromatic hydrocarbons. Olefinic hydrocarbons are not essential. Preferably, said fuels contain at least about 25 volume percent aromatics and less than 30 volume percent olefinics. The antiknock quality of these fuels will usually be above 58 Performance Number, as measured by the Research Methd of ASTM Method D 908 before addition of any tetraalkyl lead antiknock compound, and preferably above 74 Performance Number. The antiknock quality, after adding a tetraalkyl lead antiknock compound in concentrations of 2 to 4 grams of lead per gallon, will usually be above 74 Performance Number and preferably above 85 Performance Number.

The aromatic content of gasolines used in practicing this invention can be determined by any of the methods acceptable to those skilled in the art. The older chemical methods or the more recently developed physical methods may be used as desired, or methods which combine physical and chemical techniques.

The motor fuels used in practicing this invention may also contain other additives of the types normally associated with finished commercial gasolines, such as antioxidants, metal deactivators, dyes, detergents, anti-icing agents, ignition control additives, anti-rust agents, and the like.

The tetraa-lkyl lead antiknock compounds employed in the gasolines of this invention may be any of those known to the art for such purposes, but usually will be a tetraalkyl lead in which the alkyl groups contain 1-2 carbon atoms, such as tetramethyl lead, tetraethyl lead, methyltriethyl lead, dimethyldiethyl lead, and trimethylethyl lead, or a mixture of two or more of such anti-knock compounds. The antiknock compositions will also contain at least one suitable halogenated hydrocarbon scavenger for the lead in the antiknock compound, such as ethylene dichloride or ethylene dibromide or a mixture of such halogenated hydrocarbons and may also contain such dyes, stabilizers, and other components as are normally present in antiknock compositions of this type. The amount employed will usually provide from about 1 to not over 4 grams of lead for each gallon of the motor gasoline and frequently from about 2 to 3 grams of lead per gallon will be preferred. The concentration of the chlorinated hydrocarbon scavenging component will usually be between about 0.2 and 1.5 theories of chlorine, that is, the chlorinated hydrocarbon will be present in amounts providing 0.4 to 3 atoms of chlorine per atom of lead of the tetraalkyl lead antiknock compound. Preferably, the chlorinated hydrocarbon will be present in an amount which will furnish about 0.5 to 1.0 theory (1 to 2 atoms of chlorine) per molecule of tetraalkyl lead. Similarly, the grominated hydrocarbon scavenging component will be included at concentrations which will provide from 0 to about 1.0 theory of bromine, and preferably from about 0.3 to 0.8 theory (0.6 to 1.6 atoms of bromine) per molecule of tetraalkyl lead.

The molecular or molar concentration of a tetraalkyl lead antiknock compound added to a motor gasoline may be calculated from the amount of lead metal added per gallon of gasoline, that is, from the weight per gallon concentration of lead added as part of the antiknock composition. Thus, a lead concentration of 0.01 molar is obtained by adding 2.072 grams of lead (one one-hundredth of the gram atomic weight) per gallon of gasoline, no matter in what organic compound form the lead is contained in the antiknock compound or. what the concentration of the lead in the antiknock composition.

The polyacylated nitrogen bases can be considered to be derivatives of either ammonia (NH or of hydroxylamine (H NOH). Thus, if in the general formula 0 o n- )3 ..N[( l)pR'ln p is zero, the polyacyl compounds can be considered to be derivatives of ammonia and if p is 1 and n is 1 the polyacyl compounds can be considered to be derivatives of hydroxylamine. Further, if n is zero, the polyacyl compounds are triacyl derivatives of ammonia and, if n is 1 and p is zero, they are diacyl derivatives of ammonia if R is hydrogen or of an amine if R is a hydrocarbon group. Similarly, if n is 1 and p is 1 and R is a hydrocarbon group, the polyacyl compounds are triacyl derivatives of hydroxylamine.

Broadly, the polyacylated nitrogen bases of this invention have the formula wherein R is a hydrocarbon radical of 1-7 carbon atoms which is devoid of aliphatic unsaturation, R is a member of the group consisting of hydrogen and hydrocarbon radicals of 1-7 carbon atoms that are devoid of aliphatic unsaturation, at least two of the R and R groups are alkyl radicals of 1-7 carbon atoms, n is zero to 1, p is zero to l, and n is 1 whenpis 1. V

It will be understood that aliphatic unsaturation'as employed herein refers to multiple carbon-carbon bonds in aliphatic groups, such as olefinic and acetylenic groups or radicals, as distinguished from the characteristic double bonds of the benzene (aromatic) ring. Thus, a hydrocarbon radical of 1-7 carbon atoms which is devoid of aliphatic unsaturation, as employed herein, is restricted to alkyl radicals of 1-7 carbon atoms and aromatic radicals of 67 carbon atoms, i.e., the phenyl and tolyl radicals. A hydrocarbon acyl group of 28 carbon atoms, as employed herein, has the formula H or II wherein R or R is a hydrocarbon group of 1-7 carbon atoms; an alkylacyl group of 2-8 carbon atoms is a hydrocarbon acyl group in which the R or R is an alkyl group of 1-7 carbon atoms; and an arylacyl group of 7-8 carbon atoms is a hydrocarbon acyl group in which the R or R is an aryl group of 6-7 carbon atoms. Similarly, a primary hydrocarbon amine of 1.-7 carbon atoms which is devoid of aliphatic unsaturation has the formula RNH wherein R is a hydrocarbon group of 1-7 carbon atoms consisting of alkyl groups of l-7 carbon atoms and aryl groups of 6-7 carbon atoms. It will be understood further that any two or more of the hydrocarbon groups represented by R and R of the general formula may be the same or different hydrocarbon groups.

The polyacylated, nitrogen bases employed in this invention include the following subclasses:

(I) Triacylamides in which each acyl group is a hydrocarbon acyl group of 2-8 carbon atoms which is devoid of aliphatic unsaturation, at least two of said alkylacyl groups of 2-8 carbon atoms, which have the fonmula (B) Triacylamides in which 2 acyl groups are alkylacyl groups of 2-8 carbon atoms, preferably 2-5 carbon atoms, and 1 acyl group is an arylacyl group of 7-8 carbon atoms, preferably 7 carbon atoms, which are represented by diacetylbenzamide and dipropionyltoluamide m-, and p).

(H) Diacylamines in which the amine is a primary hydrocarbon amine of 1-7 carbon atoms which is devoid of aliphatic unsaturation and each acyl group is an alkylacyl group of 2-8 carbon atoms, preferably 2-5 carbon atoms, which have the formula wherein R is the hydrocarbon radical of the amine, and which include (A) Diacylamines in which the amine is a primary arylamine of 6-7 carbon atoms, preferably 6 carbon atoms, and which are represented by diacetanilide, dipropionanilide, N-phenyldi-n-butyramide, diheptanilide, diacetyl-o-toluidine, diacetyl-rri-toluidine, diacetyl-p-toluidine, diheptanoyltoluidine, isovalerylacetanilide, and formylbutyranilide; and

(B) Diacylamines in which the amine is a primary alkylamine of 1-7 carbon atoms, preferably 1-4 carbon atoms, and which are represented by N-methyldiacetamide, N-ethyl-diacetamide, N-(n-butyl)diacetamide, N- (n-butyl)dipropionamide, diheptanoylhexylamine, acetylpropionylmethylamine, acetylbutyrybutylamine, and hexanolyheptanolyheptylamine.

(III) T riacylhydroxylamines in which each acyl roup is a hydrocarbon acyl group of 2-8 carbon atoms which is devoid of aliphatic unsaturation, at least two of said acyl groups being alkylacyl groups of 2-8 carbon atoms, which have the formula wherein R is a hydrocarbon group, and which include (A) Triacylhydroxylamines in which each acyl group is an alkylacyl group of 2-8 carbon atoms, preferably 2-5 carbon atoms, and which are represented by triacetylhydroxylamine and tripropionylhydroxylamine; and

(B) Triacylhydroxylamines in which two acyl groups are alkylacyl groups of 2-8 carbon atoms, preferably 2-5 carbon atoms, and one acyl group is an arylacyl group of 7-8 carbon atoms, preferably 7 carbon atoms, and which are represented by diacetylbenzoylhydroxylamine.

(IV) Diacylamides in which each acyl group is an alkylacyl group of 2-8 carbon atoms, preferably 2-5 carbon atoms, which have the formula and are represented by diacetamide, dipropionamide, dibutyramide, diheptanoamide, acetylpropionamide, acetylbutyrarnide, acetylheptanoamide, propionylbutyramide, butyrylhexanoamide and hexanoylheptanoamide.

(V) Diacylhydroxylamines in which each acyl group is an alkylacyl group of 2-8 carbon atoms, preferably 2-5 carbon atoms, which have the formula and which are represented by diacetylhydroxylamine and dipropionylhydroxylamine.

The lead appreciators employed may be any single polyacylated nitrogen base of the defined class or subclasses or a mixture of any two or more thereof. In general, it will be preferred to employ, in decreasing order of preference, members of subclasses I, II and III, particularly the triacylamides of I (A) and the diacylamines of II (A). The most preferred lead appreciators are triacetamide and diacetanilide.

Polyacyl compounds of theSe types are well known and many members thereof are described in the chemical literature. The nomenclature for these olyacyl compounds is, however, not firmly established by convention and any particular compound can be called by several different names. Thus, the derivatives of ammonia can be named as above, or as amide derivatives of carboXylic acids, or imide derivatives of carboxylic acids, or as derivatives of nitrogen. Similarly, the derivatives of hydroxylamine can also be named as derivatives of hydroxamic acids, that is, as derivatives of N--monoacyl derivatives of hydroxylamine. The various ways in which these compounds can be named is further illustrated in the discussion and examples which follow.

The polyacylated nitrogen bases, used in the gasolines of this invention, can be prepared by a variety of methods which are well known to the art and described in the literature, including the methods briefly referred to hereinafter. Many of the derivatives of ammonia have been made by the acylation of ammonia or a primary amine or of an intermediate acylation product of ammonia or a primary amine. Thus, treatment of ammonia or an ammonium compound with acetic acid, acetyl chloride, or acetic anhydride under appropriate conditions will pr0- duce first acetamide, secondly diacetamide (also called diacetimide), and thirdly triacetamide (also called acetyl diacetimide or triacetyl nitrogen). In the same manner, polyacyl derivatives of ammonia containing different acyl groups can be prepared by treatment of an acyl amide with an acid, acid chloride, or acid anhydride containing a different acyl group. Thus, treatment of diacetamide with benzoyl chloride under suitable conditions will produce diacetylbenzamide (also called benzoyldiacetamide or benzoyldiacetyl nitrogen) which can also be produced by the action of acetic acid, acetic anhydride, or acetyl chloride or benzamide. Metallic derivatives of acyl amides can also be reacted with acyl chloride, as in the preparation of triacetamide from sodium diacetamide and acetyl chloride. A nitrile can be substituted for an amide in many similar preparations, as in the production of acetylpropionamide (also called propionylacetamide) by reaction of acetic acid with propionitrile or by the reaction of propionic acid on acetonitrile.

Polyacyl derivatives of aliphatic and aromatic amines can be prepared in similar ways. The reaction of acetic acid with methyl amine produces N-methyldiacetamide, which can also be made by the reaction of sodium diacetamide with methyl iodide. Similarly, the reaction of N-ethylacetamide and acetic anhydride produces N-ethyldiacetamide. Also, the reaction of propionic acid anhydride with aniline produces dipropionanilide. Sodium acetanilide reacts with acetyl chloride to produce diacetanilide (also called acetylacetanilide). The reaction of mercury acetanilide with isovaleryl chloride produces isovalerylacetanilide. The reaction of silver formanilide with butyryl chloride produces formylbutyrylanilide. Similar derivatives of amines can be obtained by the reaction of acyl compounds with isocyanates. Thus, N- ethyldiacetamide can be prepared from ethylisocyanate and acetic anhydride, and diacetylanilide can be prepared from phenylisocyanate and acetic anhydride.

Acetyl derivatives of ammonia and monoamines, suitable for use in the gasolines of this invention, can be prepared with particular case and convenience by the reaction of ketene with an amide or an amine. Thus, the reaction of ketene with benzamide produces acetylbenzamide and diacetylbenzamide. The reaction of ketene with aniline produces diacetanilide, and the reaction of ketene with n-butylamine produces N-(n-butyl)-diacetamide.

Two general methods have been used in preparing the polyacyl derivatives of hydroxylamine which can be used in the gasolines of this invention: (1) by acylation of a hydroxylamine or a partially acylated hydroxylamine, and (2) by the reaction of an acyl compound with an aliphatic nitro compound. Thus, O,lJ,N-triacetyihydroxylamine can be made by the reaction of acetic anhydride with either hydroxylamine hydrochloride, N-acetylhydroxylamine (acethydroxamic acid), methyl nitrate or ethyl nitrate.

The preparation of the acylated nitrogen bases, which are included in Tables I and II presented hereinafter, are described in the following examples in which the parts and proportions are by weight except where specifically indicated otherwise.

Example 1.-Triaceza mide A mixture was prepared of 59 grams of acetamide and one gram of concentrated sulfuric acid. Ketene was passed into this mixture from a ketene generator for 3.75 hours. The resulting crude product was distilled to obtain a lower boiling fraction (boiling up to 120 C., at 20 mm. pressure), 21.5 grams of a higher boiling fraction (boiling point 121 C. to 125 C., at 20 Inn. pressure), and 44 grams of residue. The higher boiling fraction and the still residue were combined and ketene was again passed through the mixture. The resulting crude product was distilled to obtain, among other fractions, 21.5 grams of material boiling at 103 C. to 110 C. at 20 mm. pressure, which fraction analyzed as containing 9.8 percent nitrogen by the Kjeldahl method (calculated for triacetamide C H O N, 9.8 percent nitrogen).

Example 2.-Diacetylbenzamicle Ketene was passed into a mixture of 6 1 grams of benzamide, 50 milliliters of benzene, and 4 milliliters of boron trifluoride etherate for 10 hours at room temperature. The resulting crude product dissolved in benzene was distilled to obtain a fraction which contained 6.4 and 6.6 percent nitrogen in duplicate analyses by the Dumas method (calculated for diacetylbenzamide, o n o -n,

. 6.38 percent nitrogen).

Example 3.-Acetylbenzamide Ketene was passed into a mixture of 61 grams of benzamide, 50 milliliters of benzene, and 1 milliliter of sulfuric acid for 10 hours at room temperature. The resulting crude product dissolved in benzene was distilled to obtain a fraction which contained 8.2 and 8.3 percent nitrogen in duplicate analyses by the Dumas method (calculated for acetylbenzamide, C H O N, 8.6 percent nitrogen).

Example 4.-Diacetanilide The procedure of Example 4 was followed, substituting equivalent amounts of ortho-, meta-, and para-toluidine isocyanates for the phenyl isocyanate of Example 4. The resultant crude products were distilled to obtain, among other fractions, the following: 1

Ex. Compound Boiling Range Pressure, Yield, mm. g. 5 Diacetyl-o-toluidine. 130 to 136 C 6. 5 15 6. DiacetyLm-toluidine... 146 to 150 8. 8 19.5

7 Diacetyl-p-toluidine. 148 to 153 Example 8.-Triacelylhydroxylamine Triacetylhydroxylamine was prepared by refluxing a mixture of hydroxylamine hydrochloride and acetic anhydride as described in the Journal of the Chemical Society, 1949, pages 3374 ff.

Example 9.-N-phenyldi-n-butyramide The procedure of Example 4 was followed for the preparation of N-phenyldi-n-butyramidle, substituting an equivalent amount of n-butyric anhydride for the acetic anhydride of Example 4. The major fraction, boiling at 147 C. to 152 C. at 1.0 mm. pressure, was found to contain 6.1% nitrogen (calculated for N-phenyldibutyramide CMHHOZN, 6.1% nitrogen).

It has been found that, in general, the eifectiveness of the polyacyl derivatives of nitrogen bases as lead ap preciators increases as their concentration increases until an excess is available, beyond which little additional benefit is obtained. The concentration of a polyacyl lead appreciator can conveniently be expressed as the ratio of the number of moles of the appreciator present in a gasoline to the number of moles of tetraalkyl lead antiknock compound present. The molecular or molar concentration of a polyacyl lead appreciator is calculated by taking the ratio of the number of grams of the appreciator in one gallon of gasoline to the molecular weight of the polyacyl compound. Thus, the addition of 14.31 grams per gallon of triacetamide (with a molecular weight of 143.1) gives a gasoline containing 0.1 mole per gallon of the additive. If the gasoline also contains 0.01 mole per gallon of a tetraalkyl lead antiknock compound, the molar ratio of the appreciator to the antiknock compound is 10 to 1.

The polyacylated nitrogen bases, used. in the gasolines of this invention, have been found to be effective in concentrations corresponding to ratios of from 1 to about 30 moles for each mole of tetraalkyl lead antiknock compound. The preferred concentration depends on the particular appreciator employed, being in the range of 1 to about 10 moles per mole of tetraalkyl lead for some polyacylated nitrogen bases such as triacetamide and diacetylbenzamide; about 10 to about 20 moles for others such as diacetanilide and triacetylhydroxylamine; and about 15 to about 30 moles for still others such as the diacetyltoluidines and N-phenyldi-n-butyramide.

In determining the effectiveness of the compounds of Examples 1 to 9 as lead appreciators, they were added in various proportions to a test fuel containing a tetraethyl lead antiknock composition and the changes in the Performance Number ratings of the fuel were determined by the Research Method procedure of ASTM Method D 908 and by the Motor Method procedure of ASTM Method D 357. The test fuel used was an aromatic reformate stock with the following composition and properties: aromatics, 47 volumes percent; olefins, 5 volume percent; saturates, 48 volume percent; API gravity, 51.5; Reid vapor pressure 7.9 lbs.; ASTM distillation, initial boiling point, 99 F.; 10% point, 138 F.; 50% point, 240 F.; point, 346 F.; end point, 424 F.; Research Performance Number (clear), 81.9; Motor Performance Number (clear), 63.9; Research Performance Number (3 ml. TEL), 100.0; Motor Performance Number (3 ml. TEL), 77.8 Performance Number. The tetraethyl lead antiknock composition used was of the: Motor Mix" formulation, containing approximately 61.4 weight percent tetraethyl lead (TEL), 17.86 weight percent ethylene dibromide (0.5 theory), 18. 81 weight percent ethylene dichloride (1.0 theory), 0.062 weight percent of dye, and 1.79 weight percent antioxidant, inerts and solvent. The tetraethyl lead antiknock composition was present at a concentration providing 3.0 milliliters of tetraethyl lead per gallon, equivalent to 3.17 grams of lead per gallon. The results are shown in Table I. l

r 3,373,000 1 ill 1 .2 TABLE I.INCREASE rN PERFORMANCE NUMBER RATINGS N ADDING ACYLATED NiTROGEN BASES TO AN AROMATIC REFORMATE oAsoLrNn CONTAINING 3 ML. TEL PER GALLON Ex. Additive 1 Triacetamide 0.6 2 Diacetylbenzamidm. 0

. Acetylbenzamide 4 Diacetanilide 5 DiacetyLo-toluidine.

6 Diacetyl-rn-toluidine- 7 Diacetyl-p-toluidine Triacetylhydroxylamine N-Phenyldi-n-butyramide 1 Outside invention, included for comparison.

The changes in Performance Number ratings in Table Weight percent basis, the following ingredients: tetraethyl I show that the compounds of all the examples, except lead, 270; triethylmethyl lead, 14.37; diethyldimethyl the acetylbenzamide of Example 3, where effective lead lead, 23.81; ethyltrimethyl lead 13.14; tetrarnethyl lead appreciators at some concentration corresponding to a 2.13; ethylene dibr-omide, 17.86 (0.5 theory); ethylene molar ratio between 2 and 16. Since the Research and dichloride 18.81 (1.0 theory); solvent, antioxidant, and Motor Methods stress fuels at different temperatures and inerts, 7.12; and dye, 0.062.

TABLE II.INGREASE IN PERFORMANCE NUMBER ON ADDING N-PHENYLDI-n-BUTYR- AMIDE TO A GASOLINE BLEND Increase in Performance Number G. Pb/gal. Research Method Motor Method Mole/g. atom Pb:

Tetraethyl lend 4. 0 0 Tetraethyl lead 1.5 0.3 0.6 0.9 -0.2 1.5 2.0

Mole/g. atom Pb:

Tetrarnix 4 6 0 6 0 e 1.5 0 5 1 5 6 "Tctramix 50-.. 1 8 0 0 6 1.2 -1 2 0 5 0 for difierent lengths of time, the changes in antiknock The changes in Performance Ratings in Table 11 show quality determined by the two procedures are, in general, antiknock concentration to be more important than ant different. A particularly attractive lead appreciator will knock composition in influence on the effectiveness of N- increase the octane ratings by both methods when present phenyldibutyramide as an antiknock appreciator. Essenat low concentrations and will usually increase the Motor tially identical Research Method responses were obtained Method Performan N mb ati o th th R with tetraethyl lead and with the redistribution mixture. search Method Performance rating and so will reduce the It will be understood that the examples, specific tests, difference between the two ratings of the fuel. Neither 45 and tables hereinbefore presented are given for illustraof these two ratings adequately predicts h ik k tive purposes solely and that this invention is not limited quality of a gasoline in an automobile engine, and s to the specific embodiments described therein. On the sort of a weighted average of the two ratings is usually other hand, it Will be readily pp to t11056 Skilled a better predictor of antiknock quality as judged, by car in the art that, subject to the limitations set forth in the Owners and drivers, so the lead appreciator giving the 5 general description, many variations can be made in the largest average increase in Research and Motor Performpolyacylated nitrogen bases, in the other materials, in the ance Number ratings at low concentrations will usually proportions, and in the techniques employed without debe preferred. Of Examples 1 to 9, the triacetamide of EX- parting from the spirit or scope of this invention.

ample 1 and the diacetanilide of Example 4 appear to give Fro th for oi it ill b apparent th t thi invene best RSUItS and are P a ly preferred. tion provides new and improved leaded motor fuels conf other measurements With the -p y y taining lead apprcciators of a novel class which improve amlde 0f EXample a test fuel Was usfid which had the the antiknock qualities of the motor fuels and which are following composition and properties: aromatics, 70 volume percent; olefins, 10 volume percent; saturates, 20 volume percent; API gravity, 43.2; Reid vapor pressure 5.7 lb.' ASTM distillation initial boiling point 101 F.

o a tribution to the art.

g z g 53 0 3 323 fg g jig g The embodiments of the invention in which an excluber m1 108.7, ml- 1153; Motor iive property or privilege is clalmed are defined as fol- Performance Number 1.5 ml. TEL) 76.9, 4.0 ml. TEL) t f 1 80.9. The effectiveness of N-phenyldi-n-butyramide as a mo or conslsung essentlany of essentially free or the disadvantages of the lead appreciators of the prior art. Accordingly, it will be apparent that this invention constitutes a valuable advance in and conlead appreciator was determined in samples of this fuel (a) Eimixtme of hydrocarbons boiling in the gasoline with various concentrations of two different tetraalkyl bolhng range: in which from 15 to about 75 Volume lead antiknock composition, with the results shown in Percent aw aromatic hydrocarbons Table II. In addition to the tetraethyl lead Motor Mix (b) an antiknock quantity of at least one tetfaalkyl formulation employed in the tests of Table I, a mixed lead antiknock Compound,

methylethyl lead antiknock composition obtained by a reat least one halogenated hydrocarbon Scavenger for distribution reaction from a mixture of tetraethyl lead theleadinthe antiknock COmPOUHd, and I and tetramethyl lead and sold commercially as Tetramix (d) from 1 to about 30 moles of a lead appreciator for 50 was used. This antiknock composition contains, on a each mole of tetraalkyl lead antiknock compound,

wherein R is a hydrocarbon radical of 1-7 carbon atoms devoid of aliphatic unsaturation, R is a member of the group consisting of hydrogen and hydrocarbon radicals of l-7 carbon atoms devoid of aliphatic unsaturation, at least two of the R and R groups are alkyl radicals of 1-7 carbon atoms, n is zero to 1, p is zero to 1, and n is 1 when p is 1.

2. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which from 15 to about 75 volume percent are aromatic hydrocarbons, (b) an antiknock quantity of at least one tetraalkyl lead antiknock compound, (c) at least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and (d) from 1 to about 30 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound, (e) said lead appreciator consisting of at least one triacylamide in which each acyl group is a hydrocarbon acyl group of 2-8 carbon atoms which is devoid of aliphatic unsaturation, at least two of said acyl groups being alkylacyl groups of 2-7 carbon atoms. 3. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which from 15 to about 75 volume percent are aromatic hydrocarbons, (b) an antiknock quantity of at least one tetraalkyl lead antiknock compound, (c) at least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and (d) from 1 to about 20 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound, (c) said lead appreciator consisting of at least one triacylamide in which each acyl group is an alkylacyl group of 2-5 carbon atoms. 4. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which from 15 to about 75 volume percent are aromatic hydrocarbons, (b) an antiknock quantity of at least one tetraalkyl lead antiknock compound, (c) at least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and (d) from 1 to about 10 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound, (e) said lead appreciator being triacetamide. 5. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which from 15 to about 75 volume percent are aromatic hydrocarbons, (b) an antiknock quantity of at least one tetraalkyl lead antiknock compound, (c) at least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and (d) from 1 to about 20 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound, (e) said lead appreciator consisting of at least one triacyla-mide in which 2 acyl groups are alkylacyl groups of 2-8 carbon atoms and 1 acyl group is an arylacyl group of 7-8 carbon atoms. 6. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which from 15 to about 75 volume percent are aromatic hydrocarbons, (b) an antiknock quantity of at least one tetraalkyl lead antiknock compound, at least one halogenated hydrocarbon scavenger for the lead in the antiknock compounds, and

(d) from 1 to about 10 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compounds,

(c) said lead appreciator being diacetylbenzamide.

7. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which from 15 to about volume percent are aromatic hydrocarbons,

(b an antiknock quantity of at least one tetraalkyl lead antiknock compound,

(c) at least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and

(d) from 1 to about 30 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound, (c) said lead appreciator consisting of at least one diacylamine in which the amine is a primary hydrocarbon amine of l-7 carbon atoms which is devoid of aliphatic unsaturation and each acyl group is an alkylacyl group of 2-8 carbon atoms.

8. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which from 15 to about 75 volume percent are aromatic hydrocarbons,

(b) an antiknock quantity of at least one tetraalkyl lead antiknock compound,

(c) at least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and

(d) from 1 to about 30 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound,

(e) said lead appreciator consisting of at least one diacylamine in which the amine is a primary arylamine of 6-7 carbon atoms and each acyl group is an alkylacyl group of 2-5 carbon atoms.

9. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which form 15 to about 75 volume percent are aromatic hydrocarbons,

(b) an antiknock quantity of at least on tetraalkyl lead antiknock compound,

(c) at least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and

(d) from 1 to about 20 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound,

(c) said lead appreciator being diacetanilide.

10. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which from 15 to about 75 volume percent are aromatic hydrocarbons,

(b) an antiknock quantity of at least one tetraalkyl lead antiknock compound,

(c) at least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and

(d) from 1 to about 30 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound,

(e) said lead appreciator consisting of at least one triacylhydroxylamine in which acyl group is a hydrocarbon acyl group of 2-8 carbon atoms Which is devoid of aliphatic unsaturation, at least two of said acyl groups being alkylacyl groups of 2-8 carbon atoms.

11. A motor fuel consisting essentially of (a) a mixture of hydrocarbons boiling in the gasoline boiling range in which from 15 to about 75 volume percent are aromatic hydrocarbons,

(b) an antiknock quantity of at least one tetraalkyl lead antiknock compound,

(c) at least one halogenated hydrocarbon scavenger for the lead in the antiknock compound, and

(d) from 1 to about 20 moles of a lead appreciator for each mole of tetraalkyl lead antiknock compound,

(c) said lead appreciator consisting of at least one triacylhydroxylamine in which each acyl group is an alkylacyl group of 2-5 carbon atoms.

15 16 12. A motor fuel consisting essentially of References Cited (21) a mixture of hydrocarbons boiling in the gasoline UNITED STATES PATENTS boiling range in which from 15 to about 75 volume pennant are aromatic hydrocarbons, 1,789,302 1/1931 Calcott et al. 4471 (b) an antiknock quantity of at least one tetraalkyl 5 3009793 11/1961 g i at E 44' 69 lead antiknock compound, 3,254,972 6/1966 Niedzlelski 252386 (c) at least one halogenated hydrocarbon scavenger for FOREIGN PATENTS the lead in the antiknock compound, and (d) from 1 to about 20 moles of a lead appreciator ifgiimedach mole of tetraalkyl lead antiknock com- 10 D ANIEL E- WYM AN, Primary Examiner. (e) said lead appreciator being triacetylhydroxylamine. Y. H. SMITH, Assistant Examiner.

230,132 9/1960 Australia.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,373,005 March 12, 1968 Edmund L. Niedzielski It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 14, line 37, for "on" read one line ,56, after "which" insert n each Signed and sealed this 10th day of June 1969.

(SEAL) Attest:

Ed '"d M. Fl

emhml' WILLIAM E. SCHUYLER JR. Attestlng Officer 7 Commissioner of Patents 

1. A MOTOR FUEL CONSISTING ESSENTIALLY OF (A) A MIXTURE OF HYDROCARBONS BOILING IN THE GASOLINE BOILING RANGE IN WHICH FROM 15 TO ABOUT 75 VOLUME PERCENT ARE AROMATIC HYDROCARBONS, (B) AN ANTIKNOCK QUANTITY OF AT LEAST ONE TETRAALKYL LEAD ANTIKNOCK COMPOUND, (C) AT LEAST ONE HALOGENATED HYDROCARBON SCAVENGER FOR THE LEAD IN THE ANTIKNOCK COMPOUND, AND (D) FROM 1 TO ABOUT 30 MOLES OF A LEAD APPRECIATOR FOR EACH MOLE OF TETRAALKYL LEAD ANTIKNOCK COMPOUND, (E) SAID LEAD APPRECIATOR CONSISTING OF AT LEAST ONE POLYACYLATED NITROGEN BASE WHICH HAS THE FORMULA (R-CO-)(3-N)-N(-(OOC)P-R'')N WHEREIN R IS A HYDROCARBON RADICAL OF 1-7 CARBON ATOMS DEVOID OF ALIPHATIC UNSATURATION, R'' IS A MEMBER OF THE GROUP CONSISTING OF HYDROGEN AND HYDROCARBON RADICALS OF 1-7 CARBON ATOMS DEVOID OF ALIPHATIC UNSATURATION, AT LEAST TWO OF THE R AND R'' GROUPS ARE ALKYL RADICALS OF 1-7 CARBON ATOMS, N IS ZERO TO 1, P IS ZERO TO 1, AND N IS 1 WHEN P IS
 1. 